1. Dxe3+? Sd3+ 2. Dg1...
1. Txc2+? Lxc2+ 2. Kc1... 
1. T4xb1? (2. Txc2+ Sxc2++) Kxc4!
1. Dc5? (2. T4xb1) Thg1! = Flight-preparing!

1. Db6! (2. Tb3+ Kxc4 3. Db5+ Kd4 4. Td3+ exd3
5. Dxd3+ Sxd3#)
1. - Txf4 → unwillingly cleaning up g-line (5. - Ke5!)
2. Dc5! (3. T4xb1 etc.) Thg1 (3. - Tgg~)
Passage through!
3. Lg7+! Txg7
And:
4. Dxe3+ Sd3 → without check, guarding c1/e1
5. Txc2+! Lxc2#!

Some curiosity also about the role of Bb1...

Destruction of black battery with fine Queen-moves at the beginning. Subtle...! Difficult and complex!
(Solvers commentaries)

Besides:
2. Dc5 Thf1 (3. - T1f~!) bzw. 2. - Tf4f2 (3. - Txe2!)
3. Dxe3+ Sd3#