Zean follow upstream until he smell rotten odor. Looks like transparent gas in this area. And there are stairs up

Perception - (1d20+9)
(19) + 9 = 28
Lock pick - (2d20L1+12)
(1218) + 12 = 24
Climbing attempt - (2d20h1)
(318) = 18
Mimic bite Vatoris - (2d20h1+5)
(513) + 5 = 18
escape grapple - (2d20L1+3)
(132) + 3 = 5
Handaxe + EC + rage to hit (advantage) - (2d20H1+8)
(1710) + 8 = 25
Handaxe + EC + rage damage - (2d6+6)
(43) + 6 = 13
Handaxe + EC + rage to hit (advantage) - (2d20H1+8)
(204) + 8 = 28
Handaxe + EC + rage damage - (2d6+6)
(54) + 6 = 15
Goading attack - (1d8)
(4) = 4
Crit damage - (2d6)
(66) = 12