diff --git a/crates/polars-io/src/csv/read/splitfields.rs b/crates/polars-io/src/csv/read/splitfields.rs
index ea6558950576..59f9bcd53bd8 100644
--- a/crates/polars-io/src/csv/read/splitfields.rs
+++ b/crates/polars-io/src/csv/read/splitfields.rs
@@ -266,21 +266,21 @@ mod inner {
                     let bytes = unsafe { self.v.get_unchecked_release(total_idx..) };
 
                     if bytes.len() > SIMD_SIZE {
-                        unsafe {
-                            let lane: [u8; SIMD_SIZE] = bytes
+                        let lane: [u8; SIMD_SIZE] = unsafe {
+                            bytes
                                 .get_unchecked(0..SIMD_SIZE)
                                 .try_into()
-                                .unwrap_unchecked_release();
-                            let simd_bytes = SimdVec::from(lane);
-                            let has_eol_char = simd_bytes.simd_eq(self.simd_eol_char);
-                            let has_separator = simd_bytes.simd_eq(self.simd_separator);
-                            let has_any = has_separator.bitor(has_eol_char);
-                            if let Some(idx) = has_any.first_set() {
-                                total_idx += idx;
-                                break;
-                            } else {
-                                total_idx += SIMD_SIZE;
-                            }
+                                .unwrap_unchecked_release()
+                        };
+                        let simd_bytes = SimdVec::from(lane);
+                        let has_eol_char = simd_bytes.simd_eq(self.simd_eol_char);
+                        let has_separator = simd_bytes.simd_eq(self.simd_separator);
+                        let has_any = has_separator.bitor(has_eol_char);
+                        if let Some(idx) = has_any.first_set() {
+                            total_idx += idx;
+                            break;
+                        } else {
+                            total_idx += SIMD_SIZE;
                         }
                     } else {
                         match bytes.iter().position(|&c| self.eof_oel(c)) {
@@ -302,7 +302,7 @@ mod inner {
             };
 
             unsafe {
-                debug_assert!(pos <= self.v.len());
+                debug_assert!(pos < self.v.len());
                 // SAFETY:
                 // we are in bounds
                 let ret = Some((self.v.get_unchecked(..pos), needs_escaping));