'No, but at least he can't send more than two walkers at it at a time,' I pointed out. 'One of the many advantages of doorways.'
'I suppose.' She looked around the car. 'We should probably make the pile bigger.'
'Unfortunately, we can't,' I said. 'The rest of the stacks are too far away to do any good, and most of the individual crates are probably too heavy for the three of us to manually move over to the pile. Time to retreat to the rear car and see what we can come up with there.'
'All right,' Bayta said. 'Rebekah?'
'I'm here,' Rebekah called, coming around from the side of the stack I'd sent her to climb.
'We're going back to the next car,' Bayta said as I took her arm and started toward the door leading to the next baggage car. 'Come on.'
'Wait a minute,' Rebekah said.
We both turned back to her. 'What is it?' Bayta asked.
Rebekah visibly braced herself. 'I was thinking maybe I should stay here.'
'Don't be ridiculous,' Bayta said firmly. 'Come on, now.'
'I'm not being ridiculous,' Rebekah countered. Her voice was trembling, but her tone was as firm as Bayta's. 'I mean …he doesn't want you and Mr. Compton.'
'If you stay, you'll be putting your people at terrible risk,' Bayta reminded her. 'You can't do that, not even for us.'
'She wouldn't be putting them at risk,' I murmured.
'If the Modhri gets hold of her—' Bayta broke off, staring at me in disbelief. 'Are you suggesting she should—?
Actually, that wasn't what I was suggesting at all. I opened my mouth to tell her so—'Mr. Compton and I have already been through this,' Rebekah said. 'I was willing to give up my life for you. I'm even more willing to give it up for the Melding.' She looked at me, a silent plea in her eyes.
I grimaced. But she was right. She and I already knew why capturing her wouldn't do the Modhri any good. With Halkan walkers beating on our front door, there was no reason why Bayta needed to know, too. After all, the Modhri might decide he wanted a prisoner or two for questioning. Better if at least one of those prisoners didn't know anything. 'Your nobility does you credit,' I went on. 'But Bayta's right. We're not leaving you behind, which means that all this conversation is doing is wasting time. So get in gear and let's go.'
Rebekah hesitated, then seemed to wilt a little. 'All right,' she said as she finally came over and joined us.
'And don't worry,' Bayta assured her, putting her arm around the girl's shoulders. 'Mr. Compton will come up with something.'
'Actually, Mr. Compton already has,' I said. 'Come on You're going to love this.'
TWENTY :
Every Quadrail passenger car came stocked with an emergency oxygen repressurization tank, a complete self- contained and self-controlled supply/scrubber/regulator system that was ready to swing into action in the highly unlikely event of a loss of air pressure in the car. The repressurization of the baggage car where the two ill-fated Halkan walkers had asphyxiated indicated that the non-passenger cars probably had the same setup.
We found the large cylinder and its associated control system in the rear car's front left-hand corner. Getting the tank off the wall, we manhandled it into the vestibule between the two baggage cars. Stripping it of its regulators took longer than I'd expected, but at last we were ready
'I don't understand how this is supposed to work,' Rebekah said as I made one last check on the tank's stability as it leaned against the vestibule wall. 'I thought these doors only locked when there was vacuum on one side.'
'Actually, the Tube isn't quite a vacuum,' I corrected. 'Seven hundred years' worth of leakage through the atmosphere barriers of multiple thousands of Quadrail stations has left a thin atmosphere out there. Not enough to breathe, but enough to keep your brains from boiling out through your ears.'
Rebekah shuddered. 'Frank!' Bayta admonished me.
'Sorry,' I apologized. 'To answer your question, your typical pressure lock doesn't know what the actual air pressure is it's dealing with. It doesn't know, and it also doesn't care. All it cares about is whether one side has significantly more pressure than the other. If and when that happens, a purely mechanical switch kicks in and locks the doors closed.'
Reaching to the top of the tank, I opened the valve, sending a hiss of cold oxygen into the vestibule and wafting into our faces. 'And as the saying goes, if you can't raise the bridge, lower the river,' I added, letting the door slide shut again. 'There should be enough air in that tank to raise the vestibule pressure at least fifty percent, probably more. The pressure lock will kick in, and at that point there'll be nothing the Modhri can do but break in the door.'
'I see,' Rebekah said. 'Though once he does that, he'll be able to get through both vestibule doors, right?'
'Actually, once he's got even a small hole or crack to let the pressure out he can get through both doors,' I said. 'But I figure it'll buy us a couple of hours.'
'Meanwhile, he's got a coral outpost out there,' Bayta murmured.
'It won't help him any,' Rebekah said.
'I don't think Bayta was referring to your coral, Rebekah,' I said. 'She was thinking about the fact that if this mind segment wants to, he could turn the entire train into walkers.'
Rebekah's face went rigid. 'Oh, no,' she breathed. 'But he wouldn't do that. Would he?'
'He did it once before,' Bayta said grimly. 'It nearly killed both of us.'
'But not quite,' I pointed out. 'But I don't think he will. Not this time. He already has plenty of walkers aboard for what he needs, and creating a bunch of new ones won't really gain him anything.'
'Unless he does it just to spite us,' Bayta said.
I shook my head. 'The Modhri doesn't seem to care that much about spite or revenge. He has a pretty good soldier mentality, actually, which is one of the things that make him so dangerous. He's too focused on his mission of galaxy domination to bother with petty distractions.'
'That might be true for the Modhri as a whole,' Rebekah said. 'But remember, all we have aboard this train is a single mind segment.'
'And you hurt him pretty badly back there,' Bayta agreed. 'The way Mr. Braithewick looked at you …Standing orders notwithstanding, he might decide to bend the rules a little.'
I hesitated, gazing at their faces, at their eyes filled with fear and compassion for all the innocent people riding our train. In theory, of course, they were right. A single mind segment, especially one that was out of touch with all the other mind segments, had a certain degree of autonomy. If it was out of touch long enough, as it would be on a long Quadrail trip, it could conceivably drift away from whatever the overall Modhran party line was at the moment.
In fact, that could be the very same mechanism that had caused the drastic change in Rebekah's batch of coral when it came under the influence of her group of rogue symbionts. If so, I could see why the Modhri was so afraid of them, and why he was going to such lengths to find and destroy them.
Should I tell them the truth? Bayta would have to be told eventually, I knew. And it might help alleviate at least this one concern for both her and Rebekah.
But this was something the Modhri definitely didn't want getting out …and he still might decide to take a prisoner for questioning. 'I doubt the Modhri's discipline is nearly that lax,' I said instead. 'Personally, I think we've got better things to worry about than having the whole train rise up against us.'
I turned back to the vestibule. 'That should be long enough,' I said. 'Let's give it a try.' Mentally crossing my
