If you think horrors beyond your comprehension was a thing just wait until you finish Sodorland Lmao. Now back to the Story! You went with major Hartley to stop Owen once and for all but did you think he would be killed so easy? he was

Major Hartley It’s over Owen! Stop this madness right now you will never bring back your der Führer!

Owen Routh You fool! You never understood! None of you! The Gotze dream was not to bring back a dictator! The Gotze dream was to bring back-

After Major Hartley shot the vat, the glass broke, causing acid to be poured all over Owen, causing him to melt into a mass of plastic before re-solidifying, killing him

His ultimate fate after this point is left unknown, as while the perfected Thomas revived everyone on Sodor after leaving his tank, the Professor wasn't among those who were brought back to life on-screen

Major Hartley Well what now…?