They explained that. He lost too much of the alien’s blood when he bled out after that accident, and was given a blood transfusion. He had to die without bleeding out or he lost the power. That’s why he killed himself sometimes if he was going to die a slow death. He no longer has time travel after waking up in the hospital. He regains it again at the end because another one of those Alphas bleeds all over him when he bombs the primary or whatever it’s called.