To escape the Deku Scrub Lockup, follow these detailed steps:

### Step 1: Obtain the Key

1. Enter the Cell: After being thrown into the Deku Scrub Lockup, you’ll find yourself in a cell with a stick but no Echoes.
2. Locate the Key: The guard will leave a key behind when they walk away from the cell door.
3. Use Tri’s Bind: Send Tri out and bind them to the key on the other side of the door. Carefully drag the key back into the cell and pick it up.

### Step 2: Unlock the Cell Door

1. Unlock the Cell: Use the key to unlock your cell door.
2. Explore the Prison: Now that you have the key, you can wander about the prison in search of an escape route. However, you can’t walk out the front door as that would be too easy.

### Step 3: Navigate Through the Prison

1. Move Boxes to Block Vision: In the northwest chamber filled with boxes and guards, use Bind to move boxes to block the Deku Scrub’s vision as you sneak past them.
2. Distract Guards: Throw and shatter pots to distract the guards when needed so you can get by.
3. Unlock the Right Cell Door: Use the prison cell key to unlock the door of the cell on the right. Move furniture around to climb up to the platform on the right.
4. Retrieve Your Gear: Head through the eastern door to find a Deku Scrub eating cotton candy off your rod. After a moment, the Deku Scrub will finish, and you’ll get all of your gear back.

### Step 4: Escape the Prison

1. Use Echoes to Escape: Now that you have everything back, you can use your Echoes to escape the prison.
2. Strike the Blue Eye: Strike the blue eye in the northern corner of the room, then enter the door to return to the main chamber in the prison.
3. Climb Over Walls: Use your echoes to climb over the walls and proceed to the east room.
4. Drop Down the Well: Hop past the last Deku Scrub and enter the room to the east. Drop down the well and swim through the passage to escape the prison.
5. Navigate Strong Currents: Swim against strong currents by either building up lots of blocks or using a Flying Tile to bypass these obstacles.
6. Deal with Bio Deku Baba Echo: Grab the Bio Deku Baba Echo and deal with it before proceeding further.
7. Reach the Exit: Use boulders and boxes to create a block between the sand and air bubbles, allowing you to swim across without being pushed down by the bubbles.
8. Collect Might Crystal (Optional): If you need to collect the Might Crystal, you can either summon a Piranha Echo and bind to it, or place a Wooden Box on the other side of the wall and float up with it.
9. Final Escape: Once you’ve navigated through all obstacles, swim out of the well and emerge on the other side. You will find yourself outside the prison, where Blossu will be waiting for you with their membership card.

By following these steps, you should be able to successfully escape the Deku Scrub Lockup.