He would die with slardar if he tried to help since they were only 2 while sentinel had 3 heroes around rune before you came and he couldn't do anything much expect auto attack since he had passive
You could let him mid even if you thought he was bad player since Alchemist was more suitable for mid since it would had bad idea having Alchemist lane with Trax since both were carry
With you didn't let him mid lead the game into worse state even if Pudge killed Alchemist since he had to share experience and his farm with you while also Pudge killed him several times due overlevel and farming, with this happened he couldn't able do anything for team since he needed level and items
You provoked him many times before he muted you