system
Given the following post, respond as if you're commenting on Reddit:
human
[MCU] Why didn't Loki use the tesseract/space-time to save himself and Thor while Thanos was fighting Hulk on the space ship?

When Loki offers the tesseract to Thanos its revealed its a trick and Hulk attacks him. He drops the space stone but Thanos is distracted so why not just use it to save him and his brother? He's selfish enough to leave hulk and Heimdall sends him back anyway.

Edit: Its meant to say "space stone" not "space time"
gpt
Loki doesn't know how to use the Tesseract, or isn't confident in his ability to use it. Not knowing how to use it would also explain why he needed planes to get around and Selvig to open a portal in Avengers. 

Loki escapes by grabbing the cube in Endgame but just ends up in some desert and is immediately captured. It's not really evidence he can teleport with any degree of accuracy. He wouldn't be aware of the Red Skull example so from his point of view the Tesseract is as likely to kill or strand the two of them as it is to save them. 

**Edited:** he lands in a desert.