I must be well out of date; I thought the B1 had an escape pod where all 4 crew members ejected together, at least that's what Rockwell's test pilots told us when they were scheduled to display it at Farnborough; they used a pair of F-111s from Upper Heyford to practice their display routine which also had escape pods.
It was great fun vectoring the F-111s round a visual circuit at 500kts with wings swept dodging all the local civil aircraft and we only had one airprox during the whole thing.