seb's a pretty serious actor and while he's not full method, he definitely kept to himself before cameras rolled to get into his character's fucked up headspace. i think it would've taken him several takes to break down if izaac was breaking character just because he's always on and prepared on set BUT he would think izaac is crazy talented and was for sure more outgoing and open to fucking around off set and at premieres and during awards season, basically everywhere else!